An image forming apparatus such as laser printer and the like comprises a sheet feed device that separates and feeds sheets, which are stacked on a feeding tray, one at a time to an image forming unit. For example, in a known image forming apparatus, sheets stacked on a feeding tray are conveyed toward a separation pad having a friction portion by a feed roller, separated one at a time when they are sandwiched between a separation roller and the separation pad (friction portion) and then fed to an image forming unit.